March 10th, 2021

лошадь, диаграмма, Фейнман

О кварках и кварк-глюонной плазме для широкой публики

Понравилась картинка-табличка с массами кварков, вот так и надо и рисовать:))

Charming Charm, Beautiful Bottom, and Quark-Gluon Plasma in the Large Hadron Collider Era: https://arxiv.org/abs/2103.05551
Santosh K. Das, Raghunath Sahoo
The primordial matter of quarks and gluons, which filled our universe just after few micro-seconds of its creation through Big Bang, is expected to be created in the laboratory by colliding nuclei at relativistic energies. The ongoing nuclear collision programs at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) are two experimental facilities, where matter in the state of Quark-Gluon Plasma (QGP) can be created and characterized. Heavy quarks, mainly charm and bottom quarks, are considered as novel probes to characterize QGP, and hence the QCD matter. Heavy quark diffusion coefficients play a significant role to understand the properties of QCD matter. Experimental measurements of nuclear suppression factor and elliptic flow are able to constrain the heavy quark diffusion coefficients, which is a key ingredient for the phenomenological study and disentangle different energy loss models. We give a general perspective of heavy quark diffusion coefficient in QGP and discuss its potential as a probe to disentangle different hadronization mechanisms, as well as to probe the initial electromagnetic field produced in non-central collisions. Experimental perspective on future measurements are discussed with special emphasis on heavy-flavors as next generation probes.
Comments: Written for general readers. Comments are welcome
лошадь, диаграмма, Фейнман

Новая система доставки пучка для протонной терапии

Почти что ведьмина служба доставки:))



Beam delivery systems for linac-based proton therapy: https://arxiv.org/abs/2103.05315
Titus-Stefan Dascalu (1), Suzanne L. Sheehy (2 and 3) ((1) Department of Physics, Imperial College London, (2) Department of Physics, University of Oxford, (3) School of Physics, University of Melbourne)
This report presents a design of a gantry for proton therapy based on the concept of adiabatic transition. The use of fixed-field alternating gradient magnets allows a large momentum acceptance and supports fast energy modulation. The optical performance of the gantry has been analysed using a beam tracking code. Several optimisations of the lattice and transition sections have been investigated to reduce size and ensure applicability to pencil beam scanning. Matching of the full energy range results in an increase in the size of the gantry, but reduces the weight and cost significantly compared to those that pertain to facilities in operation.
Comments: 14 pages, 17 figures, Submitted for the requirements of MPhys at University of Oxford
лошадь, диаграмма, Фейнман

Фрея в роли источника нейтронов:))

Должен признаться, я не знаю, существует ли общепринятый русский аналог термина spallation.

Accelerator Development at the FREIA Laboratory: https://arxiv.org/abs/2103.05265
R. Ruber, A.K. Bhattacharyya, D. Dancila, T. Ekelöf, J. Eriksson, K. Fransson, K. Gajewski, V. Goryashko, L. Hermansson, M. Jacewicz, M. Jobs, Å. Jönsson, H. Li, T. Lofnes, A. Miyazaki, M. Olvegård, E. Pehlivan, T. Peterson, K. Pepitone, A. Rydberg, R. Santiago Kern, R. Wedberg, A. Wiren, R. Yogi, V. Ziemann
The FREIA Laboratory at Uppsala University focuses on superconducting technology and accelerator development. It actively supports the development of the European Spallation Source, CERN, and MAX IV, among others. FREIA has developed test facilities for superconducting accelerator technology such as a double-cavity horizontal test cryostat, a vertical cryostat with a novel magnetic field compensation scheme, and a test stand for short cryomodules. Accelerating cavities have been tested in the horizontal cryostat, crab-cavities in the vertical cryostat, and cryomodules for ESS on the cryomodule test stand. High power radio-frequency amplifier prototypes based on vacuum tube technology were developed for driving spoke cavities. Solid-state amplifiers and power combiners are under development for future projects. We present the status of the FREIA Laboratory complemented with results of recent projects and future prospects.
Comments: 30 pages, 18 figures
лошадь, диаграмма, Фейнман

Векторный потенциал в электростатике

Какой-то ну очень необычный подход...

Electric Vector Potential Approach in Electrostatics: The Surface Electrode: https://arxiv.org/abs/2103.05438
Robert Salazar, Camilo Bayona-Roa, Gabriel Téllez
Electric vector potential Θ(r) is a legitimate but rarely used tool to calculate the steady electric field in free-charge regions. Commonly, it is preferred to employ the scalar electric potential Φ(r) rather than Θ(r) in most of the electrostatic problems. However, the electric vector potential formulation can be a viable representation to study certain systems. One of them is the surface electrode SE, a planar finite region A− kept at a fixed electric potential with the rest grounded including a gap of thickness ν between electrodes. In this document we use the \textit{Helmholtz Decomposition Theorem} and the electric vector potential formulation to provide integral expressions for the surface charge density and the electric field of the SE of arbitrary contour ∂A. We also present an alternative derivation of the result found in [M. Oliveira and J. A. Miranda 2001 Eur. J. Phys. 22 31] for the gapless (ν=0) surface electrode GSE without invoking any analogy between the GSE and magnetostatics. It is shown that electric vector potential and the electric field of the gapped circular SE at any point can be obtained from an average of the gapless solution on the gap. Keywords: Electric vector potential, surface-electrode, Helmholtz Decomposition, Green's theorem.